RFID is the use of an object (typically referred to as an RFID tag) applied to or incorporated into a product, animal, person, or any device, object, etc. for the purpose of identification and tracking using radio waves. Some tags can be read from several meters away and beyond the line-of-sight of the reader. Conventionally, a significant number of RFID applications utilize hands-free devices. This may include a wearable RFID reader device that is configured to read tags on various objects, such as inventory, boxes, etc. For hands-free devices, especially those used for RFID, designing an effective trigger system is one of the most significant challenges. Conventional triggers are cumbersome, oversized, or awkward, which fundamentally contradicts the hands-free nature of the device. In addition, since RFID technology itself is inherently passive, the trigger for RFID hands-free devices should also be passive. However, conventional hands-free systems typically include an activation mechanism such as a trigger, button, etc. Because RFID itself is a passive technology that does not require line-of-sight from the reader to the tags, the number of actions the user needs to perform to accomplish the tasks at hand is minimized. If the RFID functionality needs to be activated by a discrete action by the user, such as pushing a button, the passive nature of the device is lost. There is therefore a need for a passive triggering system that requires no user intervention whatsoever to turn on and off RFID functionality in a hands-free system, resulting in a device that is 100% passive.